Blood Types Problem Set

Problem 2: Possible blood types of offspring.

Help to answer the question

What if the mother is type O+ and the father is A-? What would the offspring's blood type be? --Mark

Tutorial

Inheritance

Both the ABO blood type alleles and the Rh factor genetic information are inherited from our parents, but they are inherited separately.

Blood types

The mother of the child is blood type 0. We know that she is homozygous. The father could be homozygous with two alleles of type A or he may be heterozygous with one allele of type A and one allele of type O. If the father is heterozygous, there is a 50% probability for a blood type A child and a 50% probability for a blood type O child. If the father is homozygous, every offspring will be blood type A.

Mother's Possible Genotype	Father's Possible Genotypes	Child's Possible Genotypes
OO	AA	AO
OO	AO	AO, OO

Rh factor

The mother of the child is Rh+. She may be homozygous or she may be heterozygous with one Rh+ allele and one Rh- allele. If the mother is heterozygous, because the father is Rh-, there is a 50% probability for an Rh+ child and a 50% probability for an Rh- child. If the mother is homozygous, every offspring will be Rh+.

Mother's Possible Rh factor	Father's Possible Rh factor	Child's Possible Rh factor
Rh+Rh+	Rh-Rh-	Rh+Rh-, Rh+Rh-
Rh+Rh-	Rh-Rh-	Rh+Rh-, Rh-Rh-

The Biology Project
Department of Biochemistry and Molecular Biophysics
University of Arizona
Thursday, October 23, 1997
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